Process for sizing spun cotton yarns

Abstract

This invention is to a process for sizing spun cotton yarns, especially dyed spun cotton yarns. The process entails treating a cotton-containing yarn with a solution polyacrylamide polymer. The use of this polymer system with a spun cotton yarn has been discovered both to overcome the previous excessive brittleness which had precluded use of polyacrylamide polymers as a size and to produce a fabric which can be overdyed without prior removal of the size.

What is claimed is: 
     
       1. A process for sizing a spun cotton yarn substrate comprising applying to the substrate an aqueous solution consisting essentially of a solution polymerized polyacrylamide homopolymer which has a viscosity of about 400 to 900 cps at 20% solids and thereafter drying the treated substrate, said homopolymer being applied in an amount sufficient to impart comprising abrasion resistance to the yarn while being capable of being removed from the yarn by aqueous washing. 
     
     
       2. The process of claim 1, wherein the amount is sufficient to improve the weaving efficiency of the yarn substrate by at least about 3% as compared to a conventional starch size composition. 
     
     
       3. The process of claim 1, wherein the cotton yarn has been dyed prior to sizing and the amount is about 4 to 8 wt %, based on the weight of the yarn. 
     
     
       4. The process of claim 3, wherein after the dyed cotton yarn is sized, it is further processed by the steps of weaving it into a fabric and then overdyeing without removal of the solution polyacrylamide polymer. 
     
     
       5. The process of claim 1, wherein the cotton yarn is an undyed towel pile yarn and the amount is about 2.25 to 4 wt %. 
     
     
       6. The process of claim 1, wherein the spun cotton yarn is selected from the group consisting of ring spun, open-end, and air-jet yarns. 
     
     
       7. The process of claim 1, wherein the viscosity is about 500 to 800 centipoise. 
     
     
       8. The treated yarn of claim 3. 
     
     
       9. The overdyed woven fabric of claim 4.